DFG-30445-000 Knowles Acoustics, DFG-30445-000 Datasheet - Page 29

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DFG-30445-000

Manufacturer Part Number
DFG-30445-000
Description
MIC SUPER CARTOID UNI DIRECT FG
Manufacturer
Knowles Acoustics
Series
DFGr
Type
Electret Condenserr
Datasheets

Specifications of DFG-30445-000

Sensitivity
-69dB ±4dB
Voltage - Rated
1.3V
Current
50µA
Size / Dimension
Circular - 2.56mm Dia x 2.69mm H
S/n Ratio
-
Filter Type
13pF
Impedance
1.7K Ohm
Frequency
100Hz ~ 5kHz
Termination
Solder Pads
Direction
Unidirectional
Port Location
Bottom and Top
Lead Free Status / Rohs Status
Lead free / RoHS Compliant
Other names
423-1150
MICROPHONE AND SPEAKER BASICS
MICROPHONES
Microphones measure sound pressure. Inside a Knowles microphone is a thin flexible diaphragm, an electrically
charged plate, and an amplifier (Fig. 1). The output voltage is proportional to changes in the small separation
between the diaphragm and the charged plate (Fig. 2).
As sound pressure inside the front cavity increases, the diaphragm is pushed closer to the plate. As the
pressure decreases, it moves further away. The motion of the diaphragm produces a small electrical signal that
is amplified by a miniature circuit inside the microphone.
The sensitivity of a typical Knowles’ microphone is measured in units of dB relative to 1 Volt per 0.1 Pascal.
Fig 1: Cross section of a Knowles EM microphone
OUTPUT TERMINAL
WIRE
AMPLIFIER
SOUND PRESSURE
CHARGE PLATE
DIAPHRAGM
FRONT CAVITY
FIG. 2: EM diaphragm and electret
CHARGE PLATE
DIAPHRAGM
AIR GAP SEPARATION
www.knowles.com
29
Note: All performance curves are typical

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